Barry Enderwick — better known online by the moniker of Sandwiches of History — has built a following of almost one million users by sharing hundreds of clips featuring recreations of long-forgotten sandwich recipes.

Enderwick has showcased regional delicacies such as the cannibal sandwich from the Midwestern United States and the late culinary icon James Beard’s beloved onion sandwichto name just two of many. Both of these dishes are delicious than you might think, but that’s not true of every ancient recipe the creator tries.

One viral sandwich Enderwick has shared doesn’t come with a strong recommendation — but it does tell us something about the era and food culture that produced it.

What is a popcorn sandwich?

Enderwick is the first to declare that the “popcorn sandwich” recipe he tested isn’t technically a sandwich. It doesn’t have a second piece of bread on top, but it does qualify as an open-faced sandwich, and it comes fromThe Up-to-Date Sandwich Booka 1909 cookbook by Eva Greene Fuller that includes 400 different sandwiches.

The popcorn sandwich isn’t for everyone — it’s not for me, and Enderwick isn’t a big fan either — but some tinned fish lovers might end up liking it. To make the sandwich, you’ll need freshly popped popcorn, sardines, salt, a pinch of cayenne pepper, ketchup, a dash of Worcestershire sauce, hot buttered toast, and Parmesan.

If you do want to try this delicacy, start by roughly chopping the popcorn and sardines. Toss them in a bowl with the salt, cayenne, Worcestershire, and enough ketchup to lightly bind everything together. Mix the ingredients until combined, then spread the mixture on the toast and grate some Parmesan on top. Pop both pieces of bread in a toaster until the cheese is bubbly, and then you’re ready to enjoy your popcorn sandwich, or at least try to.

What the popcorn sandwich tells us about American food history

Although the Earl of Sandwich, John Montagu, famously requested a piece of meat between slices of bread in 1762, ultimately giving the modern sandwich its name, the concept didn’t become widespread in the United States until the late 19th and early 20th centuries. As cities grew, workers needed filling, affordable, and portable meals, helping the sandwich gain ground quickly.

The first published recipe for a peanut butter and jelly sandwich appeared in 1901, but most sandwich recipes from this era are far different from what we eat today, as the popcorn sandwich underscores.

Although it’s an ancient grain consumed for thousands of years, popcorn became especially popular in the U.S. as an at-home snack and an affordable concession at events during the late 19th and early 20th centuries. Around the same time, ketchup became a household staple thanks to Henry J. Heinz. While recipes for ketchup had already been published, Heinz made the condiment accessible by bottling and selling it on grocery store shelves in 1876. By the early 20th century, Heinz ketchup was so popular that it had expanded internationally.

BeyondThe Up-to-Date Sandwich Bookthere isn’t an extensive written history of the popcorn sandwich. But when you consider the prominence of popcorn and ketchup at the time of its publishing, it becomes a little easier to understand why the popcorn sandwich might have been included among its 400 recipes.

Not only were tastes different in 1909, but there was also a shorter, newer history of sandwiches in the U.S. in the early 20th century, with fewer long-established rules for what does or doesn’t go together. I don’t know that we need to all be mixing popcorn with ketchup and putting it on toast, but one lesson we could learn is to get a little creative with our sandwiches this year.